Amplifier



FIG. 1 is a perspective view of an amplifier showing my new design;

FIG. 2 is a front view thereof;

FIG. 3 is a rear view thereof;

FIG. 4 is a top view thereof;

FIG. 5 is a bottom view thereof;

FIG. 6 is a right side view thereof; and,

FIG. 7 is a left side views thereof.

The broken lines shown in the drawings depict portions of the amplifier that form no part of the claimed design. 

CLAIM The ornamental design for an amplifier, as shown and described. 